pwndbg/pwndbg

Implement common convenience variables

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#2,882 opened on Apr 16, 2025

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 (3 comments) (2 reactions) (0 assignees)Python (5,820 stars) (776 forks)batch import
featurehelp wanted

Description

Is your feature request related to a problem? Please describe. Essentially I don't want to type two extra characters.

We currently define some convenience functions, and adding more would be great, like mentioned in https://github.com/pwndbg/pwndbg/issues/2849 . It can probably be implemented such that p/x $heap(offset) returns a rebased value and p/x $heap() returns just the base of the heap. However, there should be no need to type ().

Describe the solution you'd like Gdb provides a facility called convinience variables: https://sourceware.org/gdb/current/onlinedocs/gdb.html/Convenience-Vars.html For python api see https://sourceware.org/gdb/current/onlinedocs/gdb.html/Basic-Python.html and search gdb.convenience_variable and gdb.set_convenience_variable.

Additional context A user can define such a variable with set $awa = 0x1337 syntax, but even so I believe the variable names we define shouldn't have a preceding _, for example the variable for getting the base of the heap should be $heap and not $_heap because the risk of collision is really low in reality, and the _ is annoying to type.

Contributor guide

Tech stack
python
Domain
developer experiencetooling
Issue type
feature
DifficultyEstimated implementation difficulty for a new contributor, from 1 for very small changes to 5 for expert-level work.
3
Estimated timeA rough time range for an experienced contributor to investigate, implement, test, and prepare a pull request.
1-3 hours
Activity statusHow available the issue appears right now: fresh, active, stale, blocked, or waiting on maintainer input.
fresh
ClarityHow clearly the issue explains the expected change, acceptance criteria, and next step.
clear
Prerequisites
PythonGDBpwndbg
Newbie friendlinessA 1-100 score estimating how approachable this issue is for first-time contributors.
75
Research direction
Examine existing convenience functions in pwndbg to understand the pattern (e.g., in `pwndbg/commands/` directory). Use GDB Python API functions `gdb.convenience variable` and `gdb.set convenience variable` to implement a `$heap` variable that returns the base address of the heap, optionally with an offset. Ensure the variable has no leading underscore. Test with `p/x $heap(offset)` and `p/x $heap()`.